1. Field of the Invention
The present invention relates to a tape type work conveying method and apparatus, which intermittently conveys works by utilizing a continuous strip-like tape.
2. Description of the Prior Art
Various automatic assembling apparatuses have been proposed along with progress in factory automation. These automatic assembling apparatuses have technical subjects of quickly and reliably feeding works (parts) to be assembled at low cost.
More specifically, as a most popular conventional parts feeding method to an automatic assembling apparatus, a pallet system is employed. In this system, a parts carrying pallet is prepared in correspondence with outer shapes, weights, materials, and the like of parts to be fed. Parts are aligned and placed on the pallet in advance, and thereafter, the pallet is conveyed to a predetermined position. The parts are sequentially picked up from the pallet and are assembled by the automatic assembling apparatus. The pallet system is effective for relatively large parts. However, since small parts such as screws are too small and too many for the pallet system, it is difficult to apply the pallet system to these parts.
Even if the pallet system is applied to small parts such as screws, it is cumbersome and difficult to place them on a pallet while aligning their directions.
In consideration of the above drawbacks, a vibration type parts feeder system is often employed. In this system, small parts such as screws are randomly stored in a case, the case is vibrated to align the directions of the parts, and the parts can be fed one by one.
However, in both the pallet system and the vibration type parts feeder system, when a plurality of kinds of parts are to be fed, pallets or vibration type parts feeders corresponding to the outer shapes of individual parts to be fed must be prepared.
A cassette type parts feeding apparatus which can solve the above drawback is proposed in Japanese Laid-Open Patent No. 60-48855 entitled "Parts Feeding Apparatus". In this apparatus, parts are clamped between tapes arranged in a cassette to be successively stored in the cassette.
According to this proposal, however, a pick-up operation by, e.g., a robot hand equipped in an assembling apparatus cannot be performed. Repetitively adhereable tapes suffer from an adhesion limit, and must be exchanged when the adhesion limit is exceeded. In addition, the tape is slackened when it is taken up around a reel, and cannot reliably feed parts. Furthermore, since the presence/absence of parts cannot be detected, fully automatic robot hand operations cannot be performed.
The present applicant proposed a "tape type work conveying apparatus" in Japanese Patent Application Nos. 1-84881, 1-84882, 1-84883, 1-84884, and 1-84885, thereby eliminating drawbacks of the "work feeding apparatus" in Japanese Laid-Open Patent No. 60-48855 described above, and allowing fully automatic robot hand operations.
However, according to the "tape type work conveying apparatus" of the present applicant, tape drive control and work count control necessary for picking up and placing works are performed by a control means connected to a main controller of a parts assembling apparatus or a parts manufacturing apparatus comprising a robot hand, and a storage capacity of the main controller is undesirably increased, resulting in an expensive tape type work conveying apparatus.
Since the main controller detects an initial state by an initialization operation, the apparatus cannot be automatically started after a power switch is turned on.
A conveying force of each tape is controlled by setting a tension of the tape on the basis of drive control of a special-purpose motor arranged for each reel. Therefore, it is particularly difficult to perform control for preventing a cover tape from being slackened, and the cover tape is undesirably slackened.